Lorentz-Poincaré’s Nonreciprocal Relativity versus Einstein’s Reciprocal Special Relativity—A Nonrealistic Time-Shift Is Evident in the Composite Derivation of the Lorentz Transformation

While Einstein dismissed the privileged reference frame (PRF) in 1905—with the qualified acceptance by Lorentz and Poincaré (who continued their belief in a PRF)—the CMB Doppler-dipole discovery (1970s) along with a detected velocity dipole in cosmic-remote radio galaxies (2002) (noting its factor-two greater magnitude), suggest anisotropic/2-way light-speed after all. …Here we study Lorentz- Poincaré’s nonreciprocal PRF relativity versus Einstein’s reciprocal special relativity (SR) in light of the material and to-the-point Einstein quotations (1907):

       “…any two clocks of [accelerated system] Σ are synchronous with respect to [nonaccelerated reference system] S at the time t = 0, and undergo the same motion, they remain continuously synchronous with respect to S.”  (In the 2024 derivation of the Lorentz Transformation, clocks are affirmed “same motion” synchronous wrt Σ as well.)

       “On the other hand, we must not consider the [same motion] local time σ as simply the “time” of Σ, because, in fact, two [clocks] at two different points of Σ are not [synchronous] in the sense of [special relativity] when their local times σ are equal to each other.” (Partially abridged.)

which serve to confirm same-motion synchrony and also reflect the nonrealistic time-shift at the foundation of SR. The implications will be addressed within the 2024 2-way speeds of light derivation of the Lorentz transformation.